MSIX Appears to Not Include System.Text.Encodings.Web

Thanx for the reply. After posting this I learned about the Packaging Tool and was able to confirm the DLL was included in the MSIX. Turns out the problem had to do with an exception being thrown within an exception handler I'd written for my logging subsystem. Apparently that was deep enough that it just blew away the app when it occurred, leaving a trail of "off topic" and unhelpful messages (like System.Text.Encodings.Web being missing).